Modification of spontaneous emission in thin-film InGaN light-emitting diode structures

초록

The spontaneous emission characteristics in thin-film InGaN light-emitting diode (LED) structures are investigated using the three-dimensional finite-difference time-domain (FDTD) simulation. The InGaN LED structures basically consist of p-i-n GaN/InGaN heterostructures placed on a high-reflectance metal reflector. The simulation results show that light extraction efficiency has strong dependence on the quantum-well (QW) position and the GaN/InGaN film thickness, and the extraction efficiency can be enhanced by more than 5 times compared to that of conventional InGaN LED structures. In addition, the modification of spontaneous emission rate has been calculated and enhancement or suppression of spontaneous emission rate has been observed depending on the LED layer structures. It is expected that the external efficiency of thin-film LED structures can be greatly enhanced by optimizing device structures to increase the light extraction efficiency and the spontaneous emission rate.